1. Field of the Invention
The present invention pertains to labels, such as pressure sensitive labels, which contain an RFID transponder as part of the label. In particular, the invention pertains to printable labels which may be attached to an item using pressure sensitive adhesives. Images may be printed on the labels using thermal printers which rely on heat and/or pressure to create the image, such as direct thermal or thermal transfer printers. The label containing an RFID transponder may be known as a smart label.
2. Description of the Related Art
In the past, smart labels containing an RFID transponder presented many problems relating to printing on the label. The generally uneven profile of an RFID transponder, when inserted into a label by positioning the RFID within layers of the label, results in physically supported areas and unsupported areas of the face sheet of the label. The face sheet is, as a result, uneven in its profile. Previously, the use of standard paper and film materials in the construction of a smart label resulted in a non-uniform surface profile for printing. Because of this uneven profile, when attempting to print on the label utilizing a direct thermal process or a thermal transfer process, uneven images are created on the printable surface. The profile presented by the RFID chip embedded in the smart label created print voids or uneven image density because of pressure gradients as the transponder section of the label passes under the thermal print head. This circumstance can create critical problems on printed labels, in particular on bar code labels where the bar code image must be uniform enough to be scanned by an optical scanner. If the face sheet was impossible to print on because of the uneven profile, it would be necessary in the past to attempt to print around the RFID transponder contained in the label. This creates problems in printing, because in order to avoid the RFID transponder, the printer would have to avoid the transponder during the printing process, which involves identifying the exact location of the transponder prior to printing, and then controlling the printer to print around the transponder.
Another problem in prior labels is that in some applications, such as when security is a concern, it is necessary to mask the presence of an RFID transponder in a label. Prior art materials used in the construction of smart labels did not effectively mask the existence of an RFID transponder in the label. This defeats the goal of maintaining the security or the anti-counterfeiting capacity of the label.
The uneven profile printability and security problems are overcome by the present invention.
The present invention presents a label containing an RFID transponder having a more uniform profile for printing, and also for concealment of the presence of an RFID transponder within the label. The invention teaches a new structure and method for reducing the uneven profile of a label containing an RFID transponder by utilizing a unique face sheet or face sheets which minimize the difference between unsupported and supported areas along the printable surface of the label.
It is an object of the invention to present a label containing an RFID transponder having a uniform surface profile for printing.
It is a further object of the invention to present a label having a uniform profile for concealment of the presence of an RFID transponder in a label.
It is a further object of the invention to present a label having a face sheet with a relatively high density and stiffness to reduce deformation and bending in the face sheet so as to not conform unevenly to the shape of the RFID transponder.
These and other objects of the invention will be realized by the structure and method set out below.